Re: [PATCH v2 5/5] dax: handle media errors in dax_do_io

Christoph Hellwig
2016-04-20T20:59:32Z

On Fri, Apr 15, 2016 at 12:11:36PM -0400, Jeff Moyer wrote:
> > + if (IS_DAX(inode)) {
> > + ret = dax_do_io(iocb, inode, iter, offset, blkdev_get_block,
> > NULL, DIO_SKIP_DIO_COUNT);
> > + if (ret == -EIO && (iov_iter_rw(iter) == WRITE))
> > + ret_saved = ret;
> > + else
> > + return ret;
> > + }
> > +
> > + ret = __blockdev_direct_IO(iocb, inode, I_BDEV(inode), iter, offset,
> > blkdev_get_block, NULL, NULL,
> > DIO_SKIP_DIO_COUNT);
> > + if (ret < 0 && ret_saved)
> > + return ret_saved;
> > +
>
> Hmm, did you just break async DIO? I think you did! :)
> __blockdev_direct_IO can return -EIOCBQUEUED, and you've now turned that
> into -EIO. Really, I don't see a reason to save that first -EIO. The
> same applies to all instances in this patch.

Yes, there is no point in saving the earlier error - just return the
second error all the time.

E.g.

ret = dax_io();
if (dax_need_dio_retry(ret))
ret = direct_IO();